Telephone system.



A. E. LUNDELL.

TELEPHONE SYSTEM.

A'PPUCATION FILED mac. 30. ms.

1 1 337 Patented J uIy 2, 1918.

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A. E. LUNDELL.

TELEPHONE SYSTEM.

APPLICATION FILED DEC. 30. ms.

Patented July 2, 1918.

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TELEPHONE SYSTEM. APPLICATION FILED use. so. 1916.

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Patented July 2, 1918.

UNITED STATES PATENT OFFICE,

ALDEN E. LUNDELL, OF NEW YORK, N. Y., ASSIGN OR TO WESTERN ELECTRIC COI M PA'NY INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE SYSTEM.

Specification of matters Patent.

' Patented July 2,1918.

Applioetion'fllcd'neoember so, 191a. Serial No. 139,935.

To all whom it may concern.

Be it known that I, ALBEN E. LUNDELL, a citizen-of the United States, residing at New York, in the county of Bronx and State of New York, have invented certain. new and useful Improvementsdn Telephone Systems, of which the following is a full,

- ciear, concise, and exact description.

This invention relates to telephone systems, and particularly to systems of the type in which switching apparatus at the central telephone office operates automatically to find and extend the lines of calling subscribers. The invention is especially directed toward the provision of an improved or anization for preventing the connection 0 a linefinding switch with two lines simultaneously and for permitting the rapid assignment of line finding switches to lines calling simultaneously or 1n rapid suc cession, but preventing the starting of two or more line finding switches by a single calling line.

This application is in part a continuation of a prior application by the same applicant, Serial No. 16,357, filed March 23, 1915, and is related with respect to the disclosure of the means for preselecting a plurality of connecting circuits, to Patent No. 1,166,466, issued Januaryd, 1916, to the applicant herein.

In the embodiment of the invention disclosed herein, the lines are divided into groups and are multiply connected with corresponding groups of stationary terminals on a plurality of line finder switches, each of the finder switches having a set of brushes for each of the grou s of stationary terminals. The selection 0 a calling line is effected by first causing the tripping .of the set of finder switch brushes correspond:

, in with the particular group in which the ca ling line is located, and then causing the brushes to move to and stop upon the terminals of the particular line that is call-' ing. If two sets of brushes upon the finder switch should be tripped, the finder circuit would be connected with two correspondingly located lines in different groups, and the prevention of such action is one of th objects of this invention.

In this system a plurality of finder switches are provided for taking the calls as they are initiated, each finder switch in starting placing another finder switch in started. This invention.

readiness to 'be started. The calling. condition of a line which causes the startlng and group selecting operation of a finder switch may persist for some time after'the next finder switch is placed in readiness to he provides an improved organization in WhlCl'l a calling line after it has started a finder switch, is deprived of control over the starting and group selecting mechanism until the calling line is found and its starting condition altered, thus making it impossible for a single call to start and control more than one finder switch.

As the calls may, in heavy traffic periods, follow each other in rapid succession, it is desirable to provide an organization in which when one finder switch has been started in search of a calling line a second switch may be placed under control of the starting circuit with the minimum of delay. This isaccomplished, in the system of this invention, by holding one finder switch in a waiting position in operative relation with the starting circuit, ainother finder switch in an allotted position ready to move intothe waiting position when the waiting finder switch takes a call, and providing an electrically controlled allotting switch for finding idle finder switches and closing circuits to move them one at a time into the allotted position as the finder switch in that position is moved out. Thus two'or, by

a further application of the principle of t-his invention, more than two-finder switches are held in a preselected position, so that when two, or more, calls are initiated practicallysimultaneously or in rapid sucin the automatic assignment of finder switches for taking calls.

A specific embodiment of the invention in which the above-mentioned and other advantageous features are realized is illustrated in the accompanying drawings in which'Figures 1, 2, and 3, taken together, and with Fig. 1 at the left and Fig. 3 at the right of Fig. 2, represent. as much of a 'cessiona minimum of delay is necessitated complete system as is necessary to disclose by the uppermost set of brushes of each of the line finder switches. B represents one of a group of substations the lines of which terminate on another section of the panel bank. A third group of lines terminating upon still another section of the panel is indicated by the two group relays at the bottom of Fig. 1

The start relay18 (Fig. 1), is common to all of the groups of lines terminating in the several sections of the panel bank of a group of finder switches. A group cut-off relay 19 and a group lockout relay 20 are provided for each group of lines terminating on a particular section of the panel board. 21 is the usual line relay and 22 is the usual cut off relay for each line. The wires-or conductors extending from the windings of the relays 19, 19,etc., are multipled to the back and front contacts, respectively, of the inner armature of all the line relays in their respective group of lines. The conductor terminating at the back contact of each of the relays 19, 19', etc., is similarly multipled to the front contacts of the outer armatures of all the line relays of the associated group. A conductor extends from the winding of the common start relay 18 serially through normally closed contacts in the lockout relays 20, 20, etc., of the different groups, and the right-hand resting contacts of these lockout relays have multiple connection with a conductor 24 that is controlled in resting contacts of the common start relay 18.

The line finder switch mechanism to the stationary terminals or contacts of which the subscribers line circuits are connected, is illustrated diagrammatically in Fig. 2 as comprising two finder switches, the first and last in the group 01' series of switches that serve the groups of lines indicated. The finder switches may be substantially like the switch illustrated and described in the patent to James L. McQuarrie, No. 1,177,044, issued March 28, 1916.

To the upper end of each switch shaft is attached a brush arm, the brushes 35 and 73 of which cooperate with the corresponding commutator segments 34 and 44 as the shaft moves up or down. The upward and downward movement of the brushcarrying shaft of each finder switch is controlled by the up-drive magnet 5 and the down-drive magnet 45, which serve to thrust the extension 2 against one or the other of the oppositely rotating power members 3. The four contact terminals of each line for each finder switch are arranged side by side in the same horizontal line, but are shown in an inclined relation for clearness of illustration.

For each section of the panel bank there is provided a tripping device, common to all of the groups of finder switches, that includes a trip magnet 17 which when it is energized attractsits armature l6 and rotates a common trip rod 11. Upon this common tri rod are carried a number of tripping yo (cs 12, one for each of the sets of rushes of the finder switch roup. When thetrip rod is rotated, all 0 the yokes 12 are brought into position to engage the corresponding trip levers 9 on all of the finder switches, and whichever of the finder switches is started at this time has its set of brushes tripped that corresponds with this particular section of the panel bank. The brushes are normally held away from the line terminals they traverse by an insulating member carried upon the arm 8; and when the tripping lever 9 is engaged by the tripping yoke and tilted, this insulating member is withdrawn and the brushes are permitted to move toward each other so as to come into engagement with the corresponding line terminals as the switch moves up.

The finder circuits F and F, of which the line finders shown in Fig. 2 are the terminals, are illustrated in Fig. 3; and at the bottom of the figure are shown certain relays and switches which govern the assigning or allotting of the different finder circuits to the subscribers lines as they call. As this invention is not concerned with the particular manner in which the connection of a calling line shall be extended beyond the finder circuit to a called line, such extension circuits and apparatus are not illustrated. The extension of the connection beyond the finder circuit may beby means of plugs and jacks, by means of automatic switches, controlled by an operator or directly by the calling subscriber, or in any other convenient and well-known way. The sequence switches that are employed in the organization are shown diagrammatically, and may be of the type disclosed in Patent No. 1,127,808, issued February 9, 1915, to Reynolds and Baldwin. The numerals applied to contacts 66 of finder sequence switches 28 and contacts 60 of allotter sequence switch 57 indicate the only positions of the respective sequence switches in which the associated contacts are open, the numerals applied to the other contacts of each of these switches indicate the only positions of the respective switch in which the associated contacts are closed. In the following description a numeral within parentheses indicates a position in which the sequence switch contact represented by the associated number is closed. It is believed that the further details of organization of the system will appear from the description of operation of the system which follows.

When the subscriber at substation A removes the receiver from its hook, a circuit is completed from grounded battery through line relay 21, inner armature and back contact of cut-ofi relay 22, over the line, through the substation apparatus and back to ground completes a path from battery,through the right-hand winding of group cut-off relay 19, the front contact and inner armature of relay 21, conductor 23, to the multiple test contacts of the line in its section of the anel bank. This identifies this particular ine as a calling line to the line finder brushes that thereafter enga e the line terminals. The energization o relay 21 also completes a circult from battery through the left-hand armature and back contact of armature of relay 21 to ground. Relay start relay 18, right-hand normal contact of lockout relay 20, winding of said relay, back contact of relay 19, outer front contact and pulls up and completes a holding circuit for itself in series with relay 18, as follows: from battery through relay 18, left-hand front contact and armature of relay' 20,

' winding of said relay, armature and back contact of relay 19, anouter front contact and armature of relay 21, to ground. Relay 18 is energized, thus opening the initial 'energizing circuit by removing battery from the common wire 24, so that if a subscriber in some other group, as the group containing station H, calls at this instant, no battery will be supplied to the lookout relay 20' of that group, and consequently no operation will result from initiating a call until the common relay 18 is released.-

The energization of relay circuit in parallel with its own winding, this 'circuit extending by way of the front contact and right-hand armature of relay 20, and to ground through the trip magnet 17 of the corresponding group. Magnet 17 is energized and rotates the trip rod 11 so as to place the associated yokes 12 in the path of the trip levers 9 of the corresponding brushes 20 completes a of such of the switches as are in normal position.

For reasons that will hereinafter be set forth, only one of the finder circuits having accessto the groups of lines in which the calling line is located, has its sequence switch in position to be responsive to the closure of the start circuit by the energization of the relay 18. When relay 18 is energized,

it completes a circuit'from battery, through relay 25 of the finder circuit'that is in readiness, sequence switch contact 26 (1), start wire 27, front contact and armature of relay 18 to ground. Relay 25 is energized and completes a circuit from battery through sequence switch motor magnet 28, sequence switch contact 46 (1), sequence switch contact 38 (1), front contact and left-hand armature of relay 25 to ground. The finder sequence switch thereupon goes into position 2.

In position 2 a circuit is completed from battery, through the up-drive clutch magnet the preselected finder switch is moved upward. As it leaves its normal position, the set of brushes adapted to traverse the section of the panel in which the calling line terminates, is'released by means of the associated yoke 12 bemg in engagement with the trip lever 9 of that set of brushes.

Inposition 2 of the finder sequence switch, a holding circuit for relay 25 exists from battery, through the winding of said relay, front contact and right-hand armature thereof, sequence switch contact 37 (1 to 2-1/2), lower-sequence switch contact 32 (1 to 3), resistance 67, conductor 33, interrupting segment 34 and interrupter brush 35 of the line finder commutator (see Fig. 2) to ground. This circuit maintains the locking circuit of the relay 25, except when the brush 35 is in engagement with an insulating segment on the interrupter 34, which occurs only when the brushes of the switch are centrally positioned on a set of contacts in the terminal bank. Abranch from the above-traced holding circuit also extends from upper sequence switch contact 32 (1 to 3) to the test brush 36 which is adapted to traverse the test contacts associated with the test conductor 23. The test conductors 23 of all non-seeking lines of the calling line group are connected to ground through the back contacts of their respective line relays 21 and the left-hand that the brush engages one test contact before itdisengages another. Relay 19 of the group in which the calling line is located, in pulling up, breaks the holding circuit for relay 20. Relay 20 in turn opens the circuit of start relay 18 and trip magnet 17, thus returning the circuits to a condition such that a-call in a different group of lines will be immediately answered. But as relay 19 of the calling line group is kept energized to disconnect the associated relay 20 from the line relay contacts of the corresponding group until the seeking line is found, the lines ofthis particular group during this interval have no control over the group tripping magnet 17 and the starting relay 18. Thus the calling lines of some other group have the preference over calling lines that may be waiting in the group that first called. The relay 25 of 'the finder circuit and the relay 19 of the group circuit are maintained energized through the test brush 36 until the brushes of the switch are centrally positioned on the contacts of the line which has initiated the call, when a circuit will extend from battery, through the right-hand winding of relay 19, front contact and inner armature of line relay 21 of the calling line, test conductor 23, brush 36, sequence switch contact 32 (1 'to 3), sequence switch contact 37 (1 to 2-1/2), right-hand armature and front contact of relay 25, and the winding of that relay, to the same pole of the battery. As relays 19 and 25 are thus in a loop circuit that does not include a source of current, both are deenergized. Relay 25 falls back quickly, and indoing so not only opens at its left-hand front contact the circuit of the up-drive magnet 5, but also at its right-hand front contact opens the locking circuit for itself which up to that instant had been maintained alternately by way of the grounded test conductors of the non-calling lines over which the test brush 36 hadv been passing, and the commutator strip 34 and brush 35 of the line finder.

. Relay 25 releases quickl but the group cut-off relay 19 is made s ow to release its armature, as by providing its core with a copper sleeve, and before the armature is released so as to close the circuit from the ground at the line relay 21 of the calling line to the group relay 20, relay 25 of the finder circuit has fallen back and applied ground to the brush 36 and test conductor 23 by way of sequence switch contact 47 (2 t 2-1/2). Group cut-off relay 19 is thus held energized until its circuit is broken by the falling back of the armature of line relay 21. This is effected a moment later as follows: Relay 25 in falling back completes a circuit that extends from battery through sequence switch motor magnet 28, sequence switch contact 46 (2), sequence switch contact 38 (2), back contact and left-hand armature of relay 25 to ground. The sequence switch thereupon moves to position 3. In moving out of position 2 a circuit is completed from battery, through conductor 39, sequence switch contact 40 (2-1/2 to 10), brush 41, conductor 42, and cut-ofi' relay 22 to ground. Relay 22 is energized and interrupts the circuit of line relay 21, which permits its armatures to fall back, thus removing the calling ground applied to the group circuit by way of its outer armature, and at the same time deenergizing group cut-off relay 19 by breaking the circuit of the righthand winding of that relay. Thus after the calling line 1s found, the falling back of group relay 19 and closing of its normal contacts again gives the group in which the .calling line is located access to its trip magnet, and to the start relay 18 and, through it, to the finder circuits which it controls.

The talking condition of the finder circuit is that which exists when the finder sequence switch is in position 13; and the motor magnet 28 of the sequence switch is controlled to move the sequence switch through its various stages into this position by means of circuits which are not concerned with this invention, and which need not be described.

When the sequence switch reaches position 13, the talking circuit, which includes the usual repeating coil 48, answering supervisory relay 49 and calling supervisory relay 50, is completed by way of sequence switch contacts 51, 52 and 53 closed in this position. In position 13, sequence switch contacts 30 are also closed to apply battery through resistance 54 to the third conductor of the finder circuit, and thence to local conductor 42 of the line circuit, to hold the line cutoff relay 22 energized.

As long as the calling subscriber is at his telephone, the answering supervisory relay 49 remains energized and holds relay 25 energized over a circuit that extends from the winding of relay 25 to ground by way of the contacts of the relay 49 and sequence switch contacts 55 (13). Vhen the calling subscriber replaces his telephone, the falling back of relay 49 opens this circuit and permits the deenergization of relay 25. The left-hand armature of relay 25, in falling back, applies a ground for moving the finder sequence switch out of position 13 by way of a circuit which includes the motor magnet 28 of the sequence switch, and sequence switch contacts 46 (13) and 38 (13).

The finder sequence switch thereupon moves to position 15 in which it closes a circuit for the return of the finder switclnthis circuit extending from battery through down-drive magnet 45 of the finder switch, sequence switch contacts 38 (15) and the back contact and left-hand armature of relay 25 to ground. In the last stage of the downward movement of the finder switch, brush 73 grounds segment 74 of the line finder commutator. This moves the finder sequence switch out of position 15 and to position '16 by means of a circuit that includes the motor magnet 28 of the sequence switch, sequence switch contacts 56 (15), segment 74 and brush 73 of the line finder commutator to ground.

The further movement of the finder sequence switch back to its 1 or normal position is governed by circuits and apparatus that have to do with the assigning or allotting of non-busy finder circuits to the various calling lines as they initiate their calls. The assigning or allotting of the finder circuits is controlled by a sequence switch 57 and relays 58 and 59 common to all of the finder circuits and switches of the group. In the specific embodiment of the invention, illustrated, the two finder circuits F and F that are shown are assumed to be the first and last of the series or group of such circuits; and the switch contacts of the allotting shown, and an intermediate circuit that is not shown. The allotting sequence switch 57,

as indicated on the drawing, has its contacts 60 so arranged as to hold the motor magnet circuit of the switch closed excepting in positions 1,6 and 12 of the switch, while the contacts 61 are adapted to be closed in these three positions.

If it be assumed that the allotting sequence switch 57- is moved out of position 12, in a manner which will be'described hereinafter, it will rotate until it comes to position 1 where the circuit of the motor magnet will be opened in sequence switch contacts 60. When the'allotting sequence switch moves to position 1 contacts 61 of this switch close a circuit from ground to contacts 62 of the sequence switch of finder circuit F If, when this occurs, finder circuit F is busy or is awaiting a call, its sequence switch vcontacts 62 will be in some one of the positions from 1 to 15, and consequently a circuit for continuing the movement of the allotting se uence switch 57 will be completed from attery through the motor magnet of the allotting sequence switch, sequence switch contacts 62 (1 to 15) of finder circuit F contacts 61 (1) of allotting sequence switch 57 to ground. I

But if the finder circuit F has been freed, in the manner described above in tracing the establishment and disestablishment of a connection, and is available for use, its sequence 1 switch will be in position 16 and lower contact 62 (1 to 15) will be open. This being the case, when the allotting sequence switch 57 has moved to its position 1, corresponding with this finder circuit, it comes to rest, asthe circuit of its motor magnet is interrupted at lower sequence switch contacts62 of finder circuit F 4 But as sequence switch contacts 62 of the line finder F are in position 16,a circuit for moving sequence switch 28 of finder circuit F is completed from battery by way ofthe motor magnet, sequenceswitch contact 62- (16), allotting sequence switch contact 61 (1) to ground. This causes the sequence switch of finder circuit F to move to position 18, in which position the sequence switch of the finder circuit thus alloted is placed under the control of the relays 58 and 59 common to the group of finder circuits. The movement of the sequence switch of finder circuit F to position 18 leaves the allotting sequence switch 57 still in position 1, as the circuit of the'motor magnet of the allotting sequence switch still remains open in sequence switch contacts 62 of the finder switch F. i

The sequence switch of the allotted finder circuit F remains in position 18 until another one of the finder circuits which has been waiting in normal position 1 of the finder sequence switch is appropriated by a call ng line. Assuming that the waiting finder clrcuit is circuit F, when the initiation of the call causes the energization' of relay 25 of F and the movement of the associated sequence switch out of position 1 and into position 2, as previously described, the closure of sequence switch contact ,7 2 of the finder circuit F and the starting of the associated finder switch completes a circuit for the energization of the common relay 58 that extends from battery, through the winding of relay 58, by way of conductor 68, sequence switch contact 72, (2) of finder circuit F to commutator segment 44 of the associated finder switch, and thence to ground when the associated grounded brush 43 engages the segment in the upward movement of the brush shaft. Relay 58 attracts ts armatures, closing a holding circuit for itself to ground 'by way of its left-hand armature and the right-hand resting contacts of relay 59, and completing in its 'righthand contacts a circuit for the energization of relay 59 by way of conductor 64 and sequence switch contacts 46 (18') and 38 (18) of finder circuit F the sequence switch of WhlCll was moved into position 18 by the allotting sequence switch 57 in the manner already described. Relay 59 in operating call received.

In moving out of position 18, the locking circuit of relay 59 is opened in sequence switch contacts 46, thus restoring relay 59 to its normal condition. Also in moving into position 1, the sequence switch of finder circuits F closes in contacts 62 an energizing circuit for the motor magnet of the allotting sequence switch 57 to ground by way of contact 61 ('1) of the allotting sequence switch, which causes that switch to move out of position 1 and continue its movement until it finds another finder circuit that has been freed and is standing with its sequence switch in position 16, where the allotting operation as already described, is repeated. Thus each preselected finder circuit, as it is appropriated by a calling line, causes a previously allotted finder circuit to be placed in readiness to take the next call that gains access to the starting circuit, and causes the operation of the allotting sequence switch to allot another finder circuit that shall be next in order when the finder circuit held in readiness shall have been taken.

The manner in which the organization operates to prevent two or more sets of brushes of a single finder switch being tripped by simultaneously existing calls in different groups, with the consequent conrelay when the relay is operated, and the initial energizing circuits for all of the group relays are opened when the common start relay 18 is operated. The maintaining or continuing energizing circuit is closed with respect to any group relay when that relay is operated, and at the same time is interrupted with respect to any group relay beyond it in the series. The closure of the maintaining energizing circuit by the operation of any of the group relays is accompanied by the opening of the initial energizing circuit for all of the relays by the actuation of the common relay 18, whose winding is included in the continuing energizing path. Therefore, each group relay in operating acts to cut off the maintaining energizing circuit for all the group relays beyond it in the series, and also acts through the medium of the common relay 18 included in the maintaining circuit, to deprive all of the group relays of the series. of an initial energizing circuit, and, therefore, to guard against some other group relay ahead of it in the series being operated, by a call initiated a moment later, to denergize the first operated group relay.

To illustrate, it may be assumed that station A in the first group and station B in 'the second group call simultaneously. The

initial energizing circuits for both of the.

eorresponding'group relays 20 and 20 being .closed in the resting contacts of the common relay 18 and in the right-hand resting contacts of each group relay, the relays 20 and 20 are energized andstart to attract their armatures. In attracting their armatures, each group relay interrupts its initial ener gizing circuit in the right-hand resting con-,

in closing the continuing energizing path by way of its left-hand front contacts, opens that path to the relay 20 of the next group in the series and to the relays of the groups beyond. Therefore, only the group relay of the substation A group is operated to energize the associated group tripping magnet. Relay 20 of the second group, being deprived of a continuing energizing circuit, falls back and closes its resting contacts. But, in the meanwhile, the common relay 18, being included in the continuing energizing circuit that was closed by group relay 20, is operated to interrupt in its left-hand resting contacts the initial energizing circuit for all the groups. Therefore, as long as the group relay 20 remains actuated to cause the tripping of the corresponding brushes of the finder switch, no other group relay can be operated to trip its corresponding switch brushes. As soon, however, as the switch searching for the line of substation A in the first group reaches the first terminals in the bank, relays 20 and 18 are released to give the other groups control over the starting and tripping circuits, and the selection of the line of substation B in the second group immediately takes place.

The arrangement of the system is such that althougha second finder switch is; brought into operative relation with the starting circuit early in the movement of the started finder switch and before that switch has found the calling line and changed its calling condition, the second finder switch is not started by this calling line. This result is accomplished by automatically making the calling line ineffective to control the starting and group tripping circuits immediately after the started finder switch has passed its group selecting stage, and keeping the calling line ineffective to control these circuits until after the started finder switch has found the line and altered its calling condition. Thus, after the started finder switch has passed through the group selecting stage of its movement, it closes a circuit by way of the commutator segment 44 which moves the waiting on pre-selected finder circuit from position 18 to position 1 of its sequence switch, thus placing this second finder circuit in condition to respond to a closure of the starting circuit. If at this time the calling line that started the first finder switch should continue to havewcontrol over the starting circuit, this second finder switch would be started also. But an instant before the second finder switch has been placed in operative relation with the starting circuit, the test brush 36 of the started switch has closed a circuit by way of the test conductor of a non-calling line that operates the groupcut-ofi' relay 19 to release the associated relay 20 and open the starting circuit; and thereafter the relay 19 remains from control over the starting and tripping circuit until the calling line has been found,

also has the effect of giving calls in other groupscontrol over the starting and trip ping circuits'during this interval in preference to calls waiting in the same group,"thus preventing the monopolizing of the finder circuits by calls in a single group during heavy traffic periods.

What is claimed is:

1. In a telephone-\system, telephone lines,

a finder switch, a starting circuit, means for energizing said starting circuit by an line in calling to start said switch to find said line, an electromagnet for removing said starting circuit from the control of the *alling line, and an energizin circuit for said magnet maintained throug a brush of said switch and theterminals of non-calling lines. 1

2. In a telephone system, a group of telephone lines, a finder switch, a starting circuit, means for-energizing said startingcircuit by any line in calling to start said switch to find said line, an electromagnet for preventing a secondcalling line in said group from energizing said circuit, and an. energizing circuit for said magnet main-111 tained through a brush of said switch and the terminals of non-calling lines. I

3. The combination with a plurality of 1 lines, of a plurality of finder switches for making connection therewith, a startin circuit energized by any of said lines in ea in means made active in the energization 0 said starting circuit for starting one of said switches, means made operative at the outset of movement of said switch for advancing said starting circuit to the next switch, an electromagnet for preventing said calling line from st-artingsaid next/switch, and an.

energizing circuit for said electromagnet closed by said switch in its passingengagement with the terminals of non-callin lines.

5t. The combination with a plura 'ty 6f lines arrangedin groups, of a. plurality ofi finder switches adapted for group and individual line selection, a device for each group of lines for controlling the group selecting operation of saidfinder switch,- means controlled by any line of the corresponding group in calling for actuating said device, an electromagnetfor rendering'said group selecting device inefiective, andan energizing circuit for said electromagnet completed in the passing engagement of a finder switch with the non-calling line terminals of the corresponding group.

5. The combination with a plurality of telephone lines divided into groups, of a relay associated with each group and responsive to the initiation of a call in that group, a-group selecting mechanism selec* .tively controlled in the operation of the various group relays, a relay common to all of said groups, initial energizing circuits for all of said group relays controlled in normal contacts of said'common relay, and an enerizing circuit for said common relay closed 1n the operation of any of said group relays.

6. The combination with a plurality of telephonelines arranged in groups, a grouprelay associated with each group and operated by any of the lines of the corresponding group, a group selecting mechanism selectively controlled by said relays, ,a relay commonto said groups, initial energizing circuits for said group relays control ed by said common relay, and an energizingcircuit for'said common relay controlled in the operation of any of said group relays.

7:; In a telephone system, the combination with a switch having a, plurality ofnormally inactive brushes and a corresponding plurality of groups of stationary contacts arranged to be traversed by said brushes respectiv ly telephone lines arranged in' n brushes for rendering the same active, a

group-relay for each group of telephone lines, said group relay being actuated by the initiation of a call in the corresponding group, an energizing circuit for the corresponding tripping device controlled by each group. relay, a common relay,-mea-ns actuated in the operation of the same for preventing the operation of any unoperated one of said group relays, and means made act ve m the operation of any group relay for operating sald' common relay.

8. ,In a telephone system, the combination with a finder switch having stationary terminals arranged in groups and normally in: active brushes corresponding with said groups of terminals, of a tripping device for the brush of each group, telephone lines arranged in cups terminating in said groups 01E termina s,ja group relay v,for each group of lines, said group relay being responsive to the initiation of a call in the. corresponding group and controllingthe operation of the corresponding tripping device, an initial energizing circult for each of said group relays, .a common relay adapted when operated to open said initial energizing circuits and cause the movement of said finder switch, and means responsive to the operation of any of said group relays for causing the actuation of said common relay.

9. In a telephone system, the combination with a plurality oftelephone lines arranged in groups, of group selecting mechanism as necting it-from the succeeding group relays of the series.

10. The combination with a plurality of lines arranged in groups, are finder switch adapted for group and individual line selection, a relay for each group operated by any line of the group in calhng, means made active by each of said relays in operating for starting said finder switch and controlling its group selecting operation, a relay for each group acting when operated to deenergize said first-mentioned group relay, a

test conductor for each line closed as the finder switch comes into operative relation with the associated line, and an energizing circuit for said last-mentioned relay com- 80 pleted by way of the test conductors of the non-calling lines of the group.

" 11. The combination with a plurality of lines, of a plurality of finder switches for making connection therewith, a starting cir- 85 cuit for said finder switches, means under the control of any of said lines in calling for energizing said starting circuit to start a finder switch, a relay for making said lines ineffective to control said starting circuit, to and an energizing circuit for said relay completed in the passing, engagement of said started finder switch with the terminals of non-calling lines.

12. In a telephone system,-the combination as vwith 'aswitch having a plurality of normally inactive brushes and a corresponding plurality of groups of stationary contacts arranged to be traversed by said brushes respectively, of telephone llnes arranged in groups terminating in said groups of contacts, a tripping device for each set of brushes .-forrenderingthe same active, a group relay for eachgroup of telephone lines operable by the initiation of a call in the corresponding group, an energizing circuit for the corresponding tripping device controlled by each group relay, means controlled by each group relay in its operation for rendering the other group relays inoperable, means actuated upon the completion of the tripping operation of said switch for rendering the first-operated group relay inoperable and the group relays of the other groups operable by their associated telephone at lines, and means actuated by said switch in completing connection with the calling line for rendering the first-operated group relay operable by its associated lines.

13. In a telephone system, the combination with a line finder having a plurality of normally inactive brushes and a corresponding plurality of groups of stationary contacts arranged to be traversed by said brushes respectively, telephone lines arranged in groups terminating in said groups of contacts, a tripping device for each set of brushes for rendering the same active, a group relay for each group of telephone lines actuated by the initiation of a call in the corresponding group, an energizing circuit for the corresponding tripping device controlled by each group relay, means actuated in the closure of one of said energizing circuits for rendering the other energizing circuits inoperative, and means actuated in the movement of saidswitoh for restoring the operativeness of said energizing circuits. I

l t. The combination with a finder switch having a plurality of stationary terminals arranged in groups and a multiple-brush movable element with a normally inactive brush for each of said groups of stationary terminals, of a plurality of lines connected withsaid stationary terminals, an extension circuit eonnected with said multiple brushes, a tripplng device for each of said brushes, said tripping device acting when operated to make the corresponding brush active, electrically-controlled moving mechanism for said movable element, a starting magnet controlling said moving mechanism, a switch associated with each group of lines, means *controlled by said switch for operating said starting magnet and tripping device of the associated group, and means controlled 10% JOIIltly by said starting magnet and any line ma particular group for causing the operation of the aforesaid switch of said group.

15. In a telephone system, the combination with a multiple brush line finder, of 11@ electromagnetic tripping devices, one for each set of brushes, an energizing circuit having a'branch for each of said devices, an

"electromagnet in the common portion of said energizing circuit, and means controlled by said electromagnet for rendering the other branches inoperative when any one of the branches of said energizing circuit is closed.

16. In a telephone system, the combination with a multiple brush line finder, of 12@ electromagnetic tripping devices, one for each set of brushes, an energizing circuit having a branch for each of said devices,

closing means for each of said branches, a

starting magnet for said line finder in the common portion of said energizin circuit, and means controlled by said startm mag- .net for rendering the other branc es inoperative when any branch of said energizmg circuit is closed.

17. The combination with a plurality of telephone lines arranged in groups, of a group relay for each group operated by any line of the corresponding group in calling group selecting means under the control 0 said group relays, an energizing circuit having a branch for each of said group relays and a relay in the common portion of sai energizing circuit for preventin the operation of the other group relays w en any one of said group relays is operated.

18. In combination, a group of lines, a group of switches, means for operating one of said switches, a starting circuit controlled by any one of said lines for starting the operation of said switch and means common to the switches of said group for preselecting a plurality of said switches for successive operation.

19. In combination, a groupof lines, a group of switches, means for operating one of said switches, a starting circuit controlled by any one of said lines for starting the operation of said switch, and an electromagnetic switching device common 'to the switches of said group for preselecting a plurality of switches of said group for successive operation.

20. In combination, a group of lines, a group of switches for making connection therewith, means for preselecting one of said switches for operation, testing means common to the switches of said group for preselecting another of said switches for successive operation, and a starting circuit controlled by any one of said lines for starting the preselected switch operating.

21. In combination, a group of. lines, a group of switches, means for preselecting one of said switches for operation, means common to the switches offsaid group and controlled b said preselected switch for allotting another of said switches for a subsequent operation, and a starting circuit controlled by any one of said lines for starting the preselected switch operating.

22. In combination, a group of lines, a group of switches, each switch having a defi-r nite normal position, means for moving said switches out 'of their normal positlon, a starting circuit controlled by any one of said lines for starting the movement of said switches, and means controlled by the movement of a switch out of its normal position for preselecting another of said switches for operation and for selecting for the successive operation.

a third switch 23. In combination, a group of lines, a group of switches, each switch havmg a definite normal position, means for moving. a switch out of its normal position, a start-- ing circuit controlled by any one of said lines for starting the operation of said first mentioned means, and means controlled by a switch when moved out of its normal position for preselecting for successive operation a plurality of switches.

24. The combination with a plurality of means for starting said switch upon the closure of said starting circuit, means individual. to each switch for controlling the movement thereof, means actuated by the movementof said switch for operating the controlling means of a second switch from an allotted position to place said second switch in operative relation with said starting circuit, and means actuated by the operation of the controlling means of the second switch for moving the controlling means of a third switch into an allotted position.

25. The combination with a plurality of finder switches, of a starting circuit therefor, one of said finder switches being normally in operative relation with said starting circuit, means for starting said finder switch upon the actuation of said starting circuit, means actuated in the startin of said switch for moving a second switch from an allotted position into operative relation with said starting circuit, and.

means to find an idle switch and move it into the allotted position when said second switch is moved into operative relation with the starting circuit.

26. The combination with a starting circuit, of line controlled means for actuating the same, a waiting line finder switch 1noperative relation with said starting circuit,

and means made operative. to start said switch when said starting circuit is actuated, on allotted line finder adapted to be moved into waiting'position when said waiting line finder started, and means actuated to find an idle line finder and move it into the allotted position when said allotted finder is into waiting position.

In witness whereof, I, hereunto subscribe 6name this 29th day of December, A. D.

ALBEN E. LUNDELL.

moved 

